A woman suffered serious injuries after a crash between a car and a motorbike on the A413 on Saturday morning.
The accident involving a blue Nissan Qashqai and a beige motorcycle happened on Firth Hill in Great Missenden on August 5 at 7.50am.
The motorcyclist, a woman in her forties, suffered serious injuries and was taken to the John Radcliffe Hospital in Oxford where she remains in a serious but stable condition.
No one else was injured and no one has been arrested.
Investigating officer PC Dawn Seston said: “We are appealing for anyone who witnessed this collision to please come forward.
“Additionally we would ask anyone who has seen either vehicle prior to this collision to get in touch.”